This disclosure relates to a method and system for identifying subsurface formation textures and rock types included in the subsurface formation.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present techniques, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as an admission of any kind.
Wells are generally drilled into a surface (land-based) location or ocean bed to recover natural deposits of oil and natural gas, as well as other natural resources that are trapped in geological formations. A well may be drilled using a drill bit attached to the lower end of a “drill string,” which includes a drill-pipe, a bottom hole assembly, and other components that facilitate turning the drill bit to create a borehole. For oil and gas exploration and/or monitoring, it may be desirable to obtain information about the subsurface formations that are penetrated by a borehole for analysis. More specifically, this may include obtaining downhole measurements and generating images that visualize characteristics of the subsurface formations.
Petrophysical rock typing attempts to divide reservoir rocks into classes having similar flow behavior. Subdivision into classes is based on characteristics such as mineralogy, lithology, porosity and pore structure that can be investigated via downhole measurements, thin section and core description, and the use of outcrop analogs, to name a few techniques. For example, geochemical logs are one category of downhole measurement providing important information on mineralogy and lithology. However, like many logging techniques, these data may be averaged over the sensitive volume of the measurement, on the order of one foot vertically, and azimuthally from all sides of the borehole. This implies that heterogeneous distribution patterns around the borehole may not be captured. While low frequency electrical imaging tools can provide details of heterogeneous resistivity distribution around the borehole, the relationship between resistivity and rock type or texture may not be apparent.